1. Field of the Invention
The present invention relates generally to an apparatus for attaching an implement to a vehicle and particularly to an automatic quick-coupling locking mechanism for attaching a service module to a mining service vehicle.
2. State of the Art
Especially in the underground mining industry, the logistics of delivering supplies and dispatching service vehicles of all types has been one of the most costly and complex aspects of operation. Typically a large number and wide variety of specialty vehicles are utilized to perform the different mine service requirements. For example, different types of vehicles are utilized to haul pipe or timber, to transport mine personnel and to move heavy loads. The result is the expenditure of vast sums of money for both capital equipment and operating costs.
Past efforts to minimize such expenditures have included attempts to provide a standardized service vehicle which can automatically connect to and disconnect from a variety of service implements. Usually such vehicles have included a boom assembly which is mounted at the front end of the vehicle and includes a number of hydraulic cylinders for tilting and lifting the boom. Such boom assemblies typically utilize a hydraulic hitching mechanism which includes reciprocal sliding pins which when activated engage the implement and connect it to the vehicle. A sliding-pin hitch assembly of this type is taught by U.S. Pat. No. 3,760,883.
Sliding-pin hitch assemblies have a number of significant deficiencies. A major disadvantage of such assemblies is that extremely accurate alignment of the sliding pins and the receiving slots of the implement is required for proper operation of the connecting mechanism. Frequently, because the pins are the load-carrying member of the hitch assembly and because the vehicles are exposed to heavy duty service, either the pins or receiving slots of the implement become bent or damaged. Thus, manual engagement of the hitch assembly and the implement is often required, causing substantial inconvenience and loss of time, to say nothing of the safety hazards presented by such practices. The need for proper alignment of the hitch assembly and the service implement further requires that both the service vehicle and implement be located on smooth terrain. Rough terrain prevents proper alignment. Another disadvantage of sliding-pin assemblies is that the load of the service implement is carried indirectly by the hydraulic system utilized to activate the pins. Thus, a failure of the hydraulic system results in the disengagement of the implement.
In another type of hitch assembly, a pair of horizontal bars attached to a hydraulically operated lifting boom are brought into contact with a bracket attached to an implement. A hydraulic cylinder mounted generally vertically between the two horizontal hitching bars operates to force the bars apart from one another and into engagement with a pair of receiving mounts formed as part of the bracket. Hitching assemblies of this type are also dependent on a hydraulic system for secure attachment of the implement to the vehicle. A leak or failure in the hydraulic system causes the hitch assembly to become inoperative and could result in serious accident or injury. This type of system also requires a lifting boom which carries the load of the implement at a distance from the front axle of the vehicle. This presents a counterbalancing problem for low machines of the type required for underground mining.